Real-time polymerase chain reaction detection of Neisseria meningitidis in formalin-fixed tissues from sudden deaths.

Accurate identification of meningococcal sudden deaths is needed to avoid underestimation of the true incidence of the disease. This study analyzed the usefulness of a real-time polymerase chain reaction (PCR) protocol using MGB (3'-minor groove binder) probes to detect Neisseria meningitidis in formalin-fixed paraffin-embedded tissues from sudden deaths where a meningococcal fulminating infection was suspected. The protocol included detection of meningococcal DNA (ctrA gene), multiplex B/C PCR serogrouping (siaD gene), and rapid confirmation of PCR products by microcapillary electrophoresis. Sixty-nine tissues from 15 culture-confirmed meningococcal sudden deaths were analyzed (positive cases). Validation studies were performed. In each positive case, both the ctrA and the B/C siaD genes were detected. The ctrA was detected in 81.2% of the samples, whereas the serogroup (B or C) was identified in 44.9% of them. Therefore, this protocol may improve nonculture diagnosis and case ascertainment in meningococcal disease deaths, particularly when formalin-fixed tissues are the only available specimen.